In a building the structure should be free from dampness. A dam building is in healthy to these who lived in side and it causes damage to the building of the building there are various courses of dampness in the walls.
1. Moisture rising up in to the found a tin from the ground.
2. Rain beating against the walls which ay a absorb the Crain water.
3. A absorption of water from damage rain water pipes.
4. To prevent the water rising up the walls. From the foundations a special water proof layer is provided continuously on the top of the found tin. This layer is known as a horizontal dam proofing used in our country are 20mm thick cement, send rendering 112 and two coats of “bitumen” and coarse sand applied on the cement mortar bed some of o the materials used to form the horizontal dip asphalt bitumen/tar
M sot of these materials are very expensive in other countries in very dump soil for the DPC let and copper sheets are laid on 3 “thick cement concrete layers. The position of the horizontal dam proof course sold be atlas t loom a bode the ground level.
And if should be at least 50mm below the co west part of any wood member fixed to the wall
Eg;- feet of the door frame.
To preen rain H2 o passing from the top of walls, horizontal dam proof cares should be provided in immediately below the top course. Of the brick work with the walls are cohere a with roof to prevent this cause of dampness. The roof must be maintain properly.